President Obama on Monday dropped any mention of the charge he hurled days earlier at the U.S. Chamber of Commerce, that the business industry group was using foreign money to finance election year TV ads.

However, Vice President Joe Biden and the Democratic National Committee kept up the attacks, in what appeared to be an attempt to distance the president himself from the mudslinging while keeping the issue in the news, despite its crumbling credibility as an accusation.

In remarks at two separate Miami fundraisers Monday night, Obama made no reference to the explosive charge, which has largely dominated the political debate since a liberal blog first raised the issue last Tuesday.

The president’s backpedaling came as three more outlets — the Associated Press, ABC News and FactCheck.org — all published reports dismissing the accusation. That follows a report by the New York Times on Saturday that said there was “little evidence” the Chamber was engaged in unusual or improper conduct.

A senior Democratic Senate leadership aide said Monday night that the line of attack was chopped off at the knees on Sunday morning when Bob Schieffer, host of CBS’ “Face the Nation,” asked Obama adviser David Axelrod, “Is that the best you can do?”

“Once Axelrod got the treatment by Bob Schieffer, it was all over but for the shouting, and time for them to try another line of attack,” the Democrat told TheDC.

Obama had backed off the charge on Sunday in a speech to supporters in Philadelphia, saying the use of foreign funds for TV campaign ads was possible but not going so far as he had Thursday to state it as fact. But an Obama adviser said Monday morning there was “no recalibration” in the president’s remarks, and as recently as Sunday morning, the White House said they would continue to go on the offensive.

But late Monday, the Associated Press published a report with the headline: “SPIN METER: Foreign Money in Politics? Not Proven.”

FactCheck.org began its detailed report with this subheadline: “Democrats peddle an unproven claim.” Their analysis said the charge by Obama and Democrats against the Chamber has “little basis in fact.”

“It’s certainly true that millions are being spent without public disclosure, and that much of the money is coming from corporations taking advantage of a Supreme Court ruling easing restrictions on political spending,” FactCheck.org wrote. “But using foreign funds to finance political ads is still a legal violation. Accusing anybody of violating the law is a serious matter requiring serious evidence to back it up. So far Democrats have produced none.”

ABC News also did its own fact check of Obama’s attack, and found that “an examination of the evidence provides little support for the claims.”

Obama has said the Chamber’s actions are a “threat to democracy,” and a fundraising e-mail from Organizing for America, an arm of the White House, called the Chamber itself a “threat to democracy.”

And while Obama did not mention the foreign money charge Monday evening in Miami, Vice President Joe Biden raised the issue during a fundraiser in Pittsburgh.

“You don’t know where it’s coming from, but you know where it’s coming from,” Biden said of donations to groups like the Chamber. “It’s coming from some of the biggest interests.”

And the Democratic National Committee went up on the air Monday with a TV ad accusing the Chamber, along with Republican operatives Karl Rove and Ed Gillespie, of “stealing our democracy.”

Rove and Gillespie, both of whom worked in senior White House adviser roles under President George W. Bush, helped set up American Crossroads, an independent conservative group that is spending roughly $50 million in this election cycle. Rove and Gillespie do not run the group but advise the group and help raise money for it.

MoveOn.org, the liberal advocacy group, is even gathering signatures in support of a petition asking Attorney General Eric Holder to launch a criminal investigation of the Chamber.

“This is potentially a very serious crime and it is up to Attorney General Eric Holder to use his power to stop the flow of money immediately and order a full Justice Department investigation,” MoveOn.org said on its website.

Gillespie published an op-ed in the Washington Post, to be published Tuesday morning, in which he went after Obama and ThinkProgress, the blog that originally published the accusation.

“The smears are based on nothing more than a blog posting on a Web site affiliated with the Center for American Progress, a liberal nonprofit that does not disclose its donors,” Gillespie wrote.

“The fate awaiting Democrats in November is a result of their dismal economic record and their arrogance,” Gillespie said. “One reason voters are deserting President Obama in droves is because of fears of unfettered, invasive government power – fears that will only be reinforced by the Democrats’ new political vigilantism.”